Multicomponent networks, i.e., networks having two or more components, are known. Bicomponent and tricomponent networks are examples of such networks. And the utility of multicomponent networks is widespread and directed to applications suited to a particular network's physical characteristics. Known uses of prior-art multicomponent networks typically include amphiphilic networks used in ophthalamic applications.
Bicomponent networks (BCN's) traditionally have shown that the two crosslinked components at least contribute theoretically to the physical and chemical characteristics of the network. That is, the properties of a bicomponent network will reflect those of its individual components. For example, bicomponent networks containing polyisobutylenes and polysiloxanes may be of great interest to the extent that polyisobutylene is known for low cost, superior mechanical properties, extremely-low gas permeability, and excellent environmental, hydrolytic, and high temperature resistance while, in contrast, siloxanes are relatively expensive, have poor mechanical properties, but excel in regard to high gas permeability, low surface energy and bicompatibility. Thus, it is believed that elastomeric BCN's with varying ratios of polyisobutylene to polysiloxane such as polydimethylsiloxane may be of use to control gas permeability, water repellency, environmental stability, and biocompatibility.
It will be appreciated that BCN's may be formed from two components, but the second component may be used in such small and insignificant amounts that the second component doesn't contribute to the network's physical and chemical characteristics. In this instance, the network is not considered a “bicomponent network” as defined hereinabove, inasmuch as the properties of the network are essentially the same as the properties of the primary (first) component.
The prior art needs multicomponent networks having siloxane and polyurethane components due to the physical properties that such a network would possess.